Effects of soil texture and precipitation on above‐ground net primary productivity and vegetation structure across the Central Grassland region of the United States

Abstract

Abstract. A potentially important organizing principle in arid and semi‐arid systems is the inverse‐texture hypothesis which predicts that plant communities on coarse‐textured soils should have higher above‐ground net primary productivity (ANPP) than communities on fine‐textured soils; the reverse is predicted to occur in humid regions. Our objectives were: (1) to test predictions from the inverse‐texture hypothesis across a regional precipitation gradient, and (2) to evaluate changes in community composition and basal cover on coarse‐ and fine‐textured soils across this gradient to determine how these structural parameters may affect ANPP. Sites were located along a precipitation gradient through the Central Grassland region of the United States: mean annual precipitation ranges from 311 mm/y to 711 mm/y, whereas mean annual temperature ranges from 9 °C to 11 °C. For both coarse‐ and fine‐textured sites in 1993 and 1994, August ‐ July precipitation in the year of the study explained greater than 92% of the variability in ANPP. Soil texture did not explain a significant proportion of the variability in ANPP. However, soil texture did affect the proportion of ANPP contributed by different functional types. Forbs and shrubs made up a larger proportion of total ANPP on coarse‐ compared to fine‐textured sites. Shrubs contributed more to ANPP at the drier end of the gradient. Basal cover of live vegetation was not significantly related to precipitation and was similar for both soil textures. Our results revealed that across a regional precipitation gradient, soil texture may play a larger role in determining community composition than in determining total ANPP.

Soil hydrological properties regulate grassland ecosystem responses to multifactor global change: A modeling analysis

“…Among the most noticeable hypotheses is the inverse-texture hypothesis (ITH) [Noy-Meir, 1973], which states that production is higher on coarse-textured soils than that on fine-textured soils in dry regions because the water availability will be high in coarse soil in dry regions. The hypothesis has been supported by many studies [e.g., Sala et al, 1988;Lane et al, 1998;Epstein et al, 1997]. According to observations from central grassland regions in the United States, sandy soils are more productive than loamy soils when annual precipitation is less than 370 mm [Sala et al, 1988].…”

“…In central grassland region of U.S.A., the soil texture ranged from sand and sandy loam to silt loam and silt clay loam. Soil water holding capacity among those soil types ranged from 0.062 to 0.33 g water g À1 soil [Lane et al, 1998]. We assigned five soil texture types to cover the whole range in nature.…”

Factors Influencing the Abundance of Berry Plants for Black Bears, <em>Ursus americanus</em>, in Quebec

“…In the Haut-Saint-Laurent, in Quebec, Meilleur et al (1992) observed no effect of soil texture on vegetation. In a steppe in the USA, more shrub species were found in intermediate soil textures, whereas more herbaceous species were encountered when soil texture was finer (Dodd and Lauenroth 1997;Lane et al 1998). However, even in these studies, soil texture did not have a significant effect on the aboveground net primary production (Lane et al 1998).…”

Invasive Plant Species and Biomass Production in Savannas

“…In coarse soils forbs and shrubs made up a larger proportion of total productivity as compared to fine-textured sites. Thus across a regional precipitation gradient, soil texture may play a larger role in determining community composition than in determining total ANPP (Lane et al, 1998) …”